Could someone please explain why if I rotate an image in preview and save it the thumbnail remains original and if I send it to someone non mac or upload it to something like facebook the photo hasn't been rotated?

Could someone please explain why if I rotate an image in preview and save it the thumbnail remains original and if I send it to someone non mac or upload it to something like facebook the photo hasn't been rotated?

Thanks
Simon :-)

I have the same problem, I would like to know the answer to this as well